[Slick]

1) If you set the frequency to high at game setup, obviously they happen more frequently.

2) In TDM, more than one of the AI's will destroy stars in the latter stages of the game. This is speeded up by giving the AI a high bonus as it also helps their research. I don't know off the top of my head who are the frequent offenders. So it may not be just random events. Check the movement file. Check the enemy designs file in case you may have battled one of the star destroyers so you know which ship designs to look for.